1. Field of the Invention
The invention relates to a flyback power converter, and more particularly to a dual switches flyback power converter to power a high-side driver.
2. Description of the Related Art
The dual switches flyback power converter is a high efficiency power converter. The leakage inductance's energy of the transformer can be retrieved to the power rail of the power converter. A prior art has been disclosed recently, it is “Highly efficient switching power converter using a charge pump to power the drive circuit” by Yang, U.S. Pat. No. 7,460,380. However, the drawback of this prior art is a limited maximum duty cycle. The charge pump is unable to power the high-side drive circuit when the duty cycle near to the 100%. The object of the present invention is to provide an approach to solve this problem.